With CHIP assay, you cannot screen the gene. What I remember is that when
people cloned a DNA binding protein they first tried to define the target
sequence.
Make oligo (random, 10bp approx.) flanked by primer site with restriction site,
perform gel shift by using synthetic oligo as a probe, purify the DNA from
shifted band, perform PCR with primers flanking the target oligo, repeat gel
shift, and subclone the purified oligo for sequencing.